The present invention relates to a composition excellent in durability to a sterilization process and an endoscope optical system using the composition.
The durability to the sterilization process or treatment herein includes a durability under harsh conditions, for example, to so-called autoclave sterilization using saturated vapor under high temperature and pressure at about 140xc2x0 C. In these years, the autoclave sterilization involving the harsh conditions has been dominant in endoscopes which are required to be rinsed out, disinfected, and sterilized after use.
In disinfection treatments using chemicals, even if an ordinary optical glass is used for an endoscope, such a glass has no possibility of suffering from corrosion which leads to deteriorated opacity and light transmittance, because the condition of this treatment is not so harsh. In contrast, the harsh condition of the autoclave sterilization causes undesirable corrosion of the optical glass, resulting in deteriorated opacity and inability to illuminate or observe. On the other hand, no chemicals are used in the autoclave sterilization. Thus, the autoclave sterilization is not harmful to the environment and excellent in economical efficiency.
Sapphire has been known as an optical material having an excellent corrosion resistance under any harsh conditions. U.S. Pat. No. 6,038,079 discloses an example of applying sapphire to an optical system of an endoscope. In this patent, sapphire is used in a part or all of lenses for the objective optical system at the front end of the endoscope.
While sapphire advantageously has an excellent durability under harsh conditions as described above, it has the following disadvantages.
1) The high material cost of sapphire leads to a high product cost.
2) The high hardness of sapphire requires a long time for polishing to process it into an optical lens. This is not adequate to mass production.
3) The high: melting temperature of sapphire precludes the possibility of applying a postforming operation in its molten state to process it into an optical lens. This disenables sapphire to process into a complex shape such as an aspheric lens.
4) Sapphire has only one value for each of refractive index and Abbe number in optical properties thereof. Thus, it is difficult to correct an aberration sufficiently in optical design processes, resulting in deteriorated performance of the optical system.
It is therefore an object of the present invention to provide an improved composition free from the disadvantages of sapphire (in cost, hardness, workability, melting temperature, optical properties, etc) and having a sophisticated durability to a sterilization treatment.
It is another object of the present invention to provide an endoscope using the improved composition in an optical system thereof and having an effective structure capable of yielding a sufficient durability to a sterilization treatment.
In order to achieve the above object, according to the present invention, there is provided a composition having a durability to a sterilization treatment using vapor under high temperature and pressure and capable of transmitting or absorbing light, the composition comprising: a group A including 15 to 23 mol % of lanthanum oxide, 3 to 8 mol % of gadolinium oxide, 3 to 8 mol % of tantalum oxide, and 8 mol % or less of yttrium oxide; a group B including 30 to 45 mol % of boron oxide, 20 mol % or less of silicon oxide, and 20 mol % or less of germanium oxide; zero mol % of alkaline metal oxide or alkaline earth metal oxide; and a group D including 0.3 to 15 mol % of niobium oxide and 3 to 15 mol % of zirconium oxide, wherein a mol % ratio A/B between the group A and group B is 80% or more, and a dissolving-out rate of metal ion of the composition is 0.002xc3x9710xe2x88x926 mol/hour or less per square centimeter, wherein in case of applying the composition to an endoscope including an observation system and an illuminating system, an optical element disposed at the outer surface of the observation system and an optical element disposed at the outer surface of the illuminating system are formed of the composition.
The objects of the present invention are also achieved by providing a composition having a durability to a sterilization treatment using vapor under high temperature and pressure and capable of transmitting or absorbing light, the composition comprising: a group A including at least either one of lanthanum oxide, gadolinium oxide, tantalum oxide and yttrium oxide, a total mol % of the group A being 25 mol % or more; and a group B including at least either one of boron oxide, silicon oxide and germanium oxide, a total mol % of the group B being 60 mol % or less.
The objects of the present invention are also achieved by providing a composition wherein a mol % ratio A/B between the group A and group B is 80% or more.
The objects of the present invention are also achieved by providing a composition having a durability to a sterilization treatment using vapor under high temperature and pressure and capable of transmitting or absorbing light, the composition comprising: a group A including at least either one of lanthanum oxide, gadolinium oxide, tantalum oxide and yttrium oxide, a total mol % of the group A being 25 mol % or more; a group B including at least either one of boron oxide, silicon oxide and germanium oxide, a total mol % of the group B being 60 mol % or less; and a group C including 5 mol % or less of alkaline metal oxide or alkaline earth metal oxide.
The objects of the present invention are also achieved by providing a composition wherein a mol % ratio A/B between the group A and group B is 80% or more.
The objects of the present invention are also achieved by providing a composition having a durability to a sterilization treatment using vapor under high temperature and pressure and capable of transmitting or absorbing light, the composition comprising: a group A including at least either one of lanthanum oxide, gadolinium oxide, tantalum oxide and yttrium oxide, a total mol % of the group A being 25 mol % or more; a group B including at least either one of boron oxide, silicon oxide and germanium oxide, a total mol % of the group B being 60 mol % or less; and zero mol % of alkaline metal oxide or alkaline earth metal oxide.
The objects of the present invention are also achieved by providing a composition wherein a mol % ratio A/B between the group A and group B is 80% or more.
The objects of the present invention are also achieved by providing a composition having a durability to a sterilization treatment using vapor under high temperature and pressure and capable of transmitting or absorbing light, the composition comprising: a group A including at least either one of lanthanum oxide, gadolinium oxide, tantalum oxide and yttrium oxide, a total mol % of the group A being 25 mol % or more; and a group B including at least boron oxide, a total mol % of the group B being 60 mol % or less, wherein silicon oxide and germanium oxide are not included in the group B.
The objects of the present invention are also achieved by providing a composition wherein a mol % ratio A/B between the group A and group B is 80% or more.
The objects of the present invention are also achieved by providing a composition having a durability to a sterilization treatment using vapor under high temperature and pressure and capable of transmitting or absorbing light, the composition comprising: a group A including at least either one of lanthanum oxide, gadolinium oxide, tantalum oxide and yttrium oxide, a total mol % of the group A being 25 mol % or more; a group B including at least boron oxide, a total mol % of the group B being 60 mol % or less, wherein silicon oxide and germanium oxide are not included in the group B; and zero mol % of alkaline metal oxide or alkaline earth metal oxide.
The objects of the present invention are also achieved by providing a composition wherein a mol % ratio A/B between the group A and group B is 80% or more.
The objects of the present invention are also achieved by providing a composition having a durability to a sterilization treatment using vapor under high temperature and pressure and capable of transmitting or absorbing light, the composition comprising: a group A including at least either one of 13 to 35 mol % of lanthanum oxide, 16 mol % or less of gadolinium oxide, 16 mol % or less of tantalum oxide, and 16 mol % or less of yttrium oxide, a total mol % of the group A being 25 mol % or more; a group B including at least either one of 22 to 60 mol % of boron oxide, 25 mol % or less of silicon oxide, and 25 mol % or less of germanium oxide, a total mol % of the group B being 60 mol % or less; a group C including 5 mol % or less of alkaline metal oxide or alkaline earth metal oxide; and a group D including at least either one of 0.3 to 15 mol % of niobium oxide and 3 to 15 mol % of zirconium oxide.
The objects of the present invention are also achieved by providing a composition wherein a mol % ratio A/B between the group A and group B is 80% or more.
The objects of the present invention are also achieved by providing an endoscope using the composition wherein an optical element disposed at an outer surface of an optical system of the endoscope is formed of the composition.
The objects of the present invention are also achieved by providing an endoscope wherein the optical system includes an observation system and an illuminating system, wherein at least either one of an optical element disposed at the outer surface of the observation system and an optical element disposed at the outer surface of the illuminating system is formed of the composition.
The objects of the present invention are also achieved by providing an endoscope wherein the optical system includes an observation system and an illuminating system, wherein all of an optical element disposed at the outer surface of the observation system and an optical element disposed at the outer surface of the illuminating system are formed of the composition.
The objects of the present invention are also achieved by providing an endoscope using the composition wherein a surface of an optical element disposed at an outer surface of an optical system of the endoscope is formed of the composition.
The objects of the present invention are also achieved by providing an endoscope wherein the optical system includes an observation system and an illuminating system, wherein at least either one of a surface of an optical element disposed at the outer surface of the observation system and a surface of an optical element disposed at the outer surface of the illuminating system is formed of the composition.
The objects of the present invention are also achieved by providing an endoscope wherein the optical system includes an observation system and an illuminating system, wherein all of a surface of an optical element disposed at the outer surface of the observation system and a surface of an optical element disposed at the outer surface of the illuminating system are formed of the composition.
The objects of the present invention are also achieved by providing an endoscope using the composition which includes an objective lens unit for imaging an object on a front end of an insertion section of the endoscope, wherein an optical element located proximal to the object side of the objective lens unit and an optical element located proximal to the image side of the objective lens unit are formed of the composition.
The objects of the present invention are also achieved by providing an endoscope wherein all of optical elements of the objective lens unit are formed of the composition.
The objects of the present invention are also achieved by providing an endoscope wherein the optical element located proximal to the image side of the objective lens unit is a convex lens.
The objects of the present invention are also achieved by providing an endoscope wherein the optical element located proximal to the image side of the objective lens unit is either one of an absorption type infrared cut-off filter and an interference type infrared cut-off filter.
The objects of the present invention are also achieved by providing an endoscope using the composition which includes, in order from the object side of the endoscope, an image guide and an ocular lens unit, wherein an optical element located proximal to the image guide side of the objective lens unit and an optical element located proximal to the observation side of the objective lens unit are formed of the composition.
The objects of the present invention are also achieved by providing an endoscope wherein all of optical elements of the ocular lens unit are formed of the composition.
The objects of the present invention are also achieved by providing an endoscope wherein at least a part of the image guide is formed of the composition.
The objects of the present invention are also achieved by providing an endoscope using the composition which includes an image pickup device for imaging an object on a front end of an insertion section of the endoscope, wherein an optical element located proximal to the object side of the image pickup device is formed of the composition.
The objects of the present invention are also achieved by providing an endoscope using the composition which includes, in order from the object side at a front end of an insertion section of the endoscope, an illuminating unit and a light guide, wherein an optical element located proximal to the object side of the illuminating unit and an optical element located proximal to the light guide side of the illuminating unit are formed of the composition.
The objects of the present invention are also achieved by providing an endoscope wherein all of optical elements of the illuminating unit are formed of the composition.
The objects of the present invention are also achieved by providing an endoscope wherein at least a part of the light guide is formed of the composition.
The objects of the present invention are also achieved by providing an endoscope using the composition which includes, in order from the light source side of the endoscope, an incident unit and a light guide, wherein an optical element located proximal to the light source side of the incident unit and an optical element located proximal to the light guide side of the incident unit are formed of the composition.
The objects of the present invention are also achieved by providing an endoscope wherein all of optical elements of the incident unit are formed of the composition.
The objects of the present invention are also achieved by providing an endoscope, wherein the incident unit includes a columnar rod-shaped optical element, wherein the rod-shaped optical element is formed of the composition.
The objects of the present invention are also achieved by providing a composition having a durability to a sterilization treatment using vapor under high temperature and pressure and capable of transmitting or absorbing light, wherein a dissolving-out rate of metal ion of the composition is 0.002xc3x9710xe2x88x926 mol/hour or less per square centimeter.
The objects of the present invention are also achieved by providing a composition wherein the dissolving-out rate of metal ion of the composition is 0.0005xc3x9710xe2x88x926 mol/hour or less per square centimeter.
Other features and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description.